Vladimir Putin was today confirmed as Russia's new prime minister by the country's lower house of parliament in a move that formalises his power-sharing role with the new president Dmitry Medvedev.

Deputies in Russia's state duma voted overwhelmingly to support Putin's candidacy – by 392 to 56 votes. Only the communists voted against. MP's from Putin's United Russia party then led a standing ovation.

Today's widely anticipated move follows the inauguration yesterday of 42-year-old Medvedev – Putin's close ally - as Russia's third post-Soviet leader. Immediately after today's vote Medevev said he would pass a decree formally naming Putin as head of Russia's new government.

Both men are now expected to run Russia in a tandem, with Putin wielding considerable influence from the prime minister's office in Russia's White House. This morning both men sat side by side in the packed duma, further confirming Russia's new political dynamic.

In a wide-ranging address to MPs, Putin this morning set out the new government's priorities. He said Russia was determined to overtake Britain as the world's sixth leading economy later this year.

His government would also tackle the country's myriad economic problems – including its "alarming" inflation rate, Putin said. He also promised to persuade Russian to smoke and drink less – a big task. "We need an information campaign to advocate healthy living," he declared.

Before the vote, Medvedev told the duma he was proposing Putin for the prime minister's job, adding that "Vladimir Vladimirovich" needed no introduction. "I think nobody doubts that our tandem, our co-operation will only strengthen," Medvedev said. Putin would "play a key role" in implementing policy, he said.

Medvedev also lauded Putin's hawkish policies towards the west during his eight years as president. "We know that great changes have taken place in respect of Russia's role on the international stage. Russia is once again internationally respected," he said.

Political analysts are not clear as to whether Putin intends to return as president in 2012 - after serving a four-year stint as prime minister. They agree, however, that he is likely to remain the dominant figure in Russian politics, with Medvedev a junior partner.

Critics say the show of solidarity masks fears that Putin has navigated Russia into a dangerous period of political uncertainty, with two centres of power taking shape in a potentially debilitating and divisive arrangement.

Under the constitution, the prime minister temporarily replaces a president who dies or is incapacitated.

Putin, 55, a longtime KGB officer, served as prime minister for five months in 1999 under Boris Yeltsin, who stepped down unexpectedly on December 31 of that year and handed him the presidency. Putin was elected to his first term three months later.